1. Field of the Invention
This invention relates generally to apparatus and methods for concentrating waste materials and more specifically to concentrators particularly adapted for the volumetric reduction of waste solutions such as the effluent from photoprocessing laboratories.
2. Discussion of the Prior Art
Increasing concern over pollution of the environment has created an escalating demand for apparatus and methods which will eliminate or at least minimize the discharge of waste materials into the environment. In recent years, the focus has been primarily on large-scale operations, such as refineries or chemical plants, which have been carefully monitored and forced to develop zero discharge processes. More recently, the focus has begun to shift to small scale polluters such as those associated with photoprocessing laboratories (including mini-labs), x-ray laboratories (primarily in hospitals and doctor's offices), printing and engraving shops, and biological laboratories. Acid solutions associated with circuit board etching and metal plating have also been of concern along with the solvents and cutting fluids associated with machine shops, garages and paint shops.
All of these solutions are harmful if not toxic and therefore are potentially damaging to the atmosphere. Even though these are typically small scale operations, the number of such operations is large so that the overall volume of waste is significant.
Liquid wastes are far more difficult and expensive to process for disposal than are solid wastes. For this reason, the purpose of most recovery devices associated with liquid waste is either to reclaim the liquid solvent, leaving only the solid residue, or to concentrate the solution so as to reduce the quantity of the contaminated waste. In the case of aqueous wastes, the solvent (water) need not be recycled to the process but may be discharged to a drain if it is sufficiently pure.